This is the noise I hear in my 1983 rabbit gti when accelerating hard forward, either from a standstill or while rolling. Taking off hard in reverse produces no noise. Also, the noise is more difficult to reproduce when the engine is cold.
I just replaced all four engine /gearbox mounts but the noise is still there. I have to say that i also have chatter when engaging the clutch quickly, not sure if they could be related.
It sounds like something rubbing against a rotating member - something touching the drive shaft under load maybe? I guess I could check the clearance between the drive shafts and anything near by. I do have the gokraut underbody x/k brace installed, and a tech tonics exhaust. Any ideas on how I can diagnose this?